The US Army Corps of Engineers on Tuesday said it will approve a permit to allow for the completion of the controversial Dakota Access pipeline.

After months of protests by Native Americans and their supporters, the US Army Corps of Engineers - which has approval authority - had under the Obama administration put the plans on hold pending further environmental review.

But President Donald Trump has supported the 1,172-mile (1,886-kilometer) oil pipeline, which would snake through four US states, and ordered officials to reconsider.

"The Department of the Army announced today that it has completed a presidential-directed review of the remaining easement request for the Dakota Access pipeline, and has notified Congress that it intends to grant an easement for a right-of-way across government land at Lake Oahe Dam and Reservoir, North Dakota," the Army said in a statement.

An easement is a special permit that allows an entity or person to cross someone else's land.

The Army said the approval will "facilitate completion" of the last stretch of pipeline connecting the Bakken and Three Forks oil production areas in North Dakota to an existing crude oil terminal near Pakota, Illinois.

Thousands of protesters had camped in freezing winter temperatures to block the pipeline's planned route, which the Standing Rock Sioux Tribe says creates a risk of water pollution and endangers areas with sacred historic sites and artifacts.

The standoff - which included some 2,000 military veterans who joined the protest - set off violent clashes with law enforcement as well as sympathetic demonstrations nationwide.

Jan Hasselman, an attorney at the environmental organization Earthjustice, which is representing the Standing Rock Sioux Tribe, said in a statement that the Obama administration had correctly sought to address the tribe's concerns, and that further study of the pipeline route was needed.

"Trump's reversal of that decision continues a historic pattern of broken promises to Indian Tribes and a violation of Treaty rights," Hassleman said. "Trump and his administration will be held accountable in court."

Tiernan Sittenfeld of the League of Conservation Voters called the Trump administration's go-ahead of the project "disgraceful" and a signal that it is "putting polluting corporations before the rights of communities to breathe clean air, have access to safe drinking water."